This chapter reviews the current knowledge of spot form and net form of net blotch of barley with an emphasis on recent genetic studies and their contribution to our understanding of the range of host-pathogen genetic interactions. Principal differences between the two forms of the disease are explained together with common cultural control methods. An example of a practical approach in breeding for durable resistance in South Australia is provided, and we discuss what such experience and genetic studies imply for successful breeding strategies for stable resistance.